Control BGP Communities

Control BGP communities for AS203314 traffic engineering, including blackhole, propagation control, and path prepending.

Control communities allow you to dictate prefix announcements and manipulate path attributes dynamically. Attach these communities to routes you announce to AS203314 to control how we propagate them.

Traffic Engineering: These communities give you fine-grained control over route propagation and path prepending outside Hats Network.

Blackhole & Filtering

Community	Action
`203314:0:666`	Do not announce this route (blackhole)

Usage: Stop announcement of a prefix (e.g., during DDoS mitigation or IP address deprecation).

Note: Equivalent to standard blackhole community 65535:65281.

Propagation Control

Control which types of peers receive your routes:

Community	Action
`203314:1:0`	Do not send to Upstream
`203314:1:1`	Do not send to Peering
`203314:1:2`	Do not send to Downstream

Example Use Cases:

Use 203314:1:0 to prevent transit from carrying your prefix
Use 203314:1:1 to keep traffic limited to IX route servers
Use 203314:1:2 to prevent customer leakage

Geographic Restrictions

Control route propagation based on location:

Community	Action
`203314:2:1`	Do not send to other regions (Disable Cross Region)
`203314:2:2`	Do not send to other PoPs (Disable Cross PoP)
`203314:201:XX`	Do not send to Region `XX`

Examples:

# Keep traffic within Asia only
203314:2:1         # Disable cross-region
203314:201:300     # Exclude North America
203314:201:200     # Exclude Europe

Community	Action
`203314:202:XXX`	Do not send to PoP `XXX`

Examples:

# Exclude specific PoPs
203314:202:301     # Do not announce via Seattle
203314:202:131     # Do not announce via Tokyo
203314:202:102     # Do not announce via Hong Kong HKG2

Path Prepending

Control AS-path prepending for routes outside Hats Network:

Scope: Path prepending only affects routes announced to external peers (upstream, peering, customers)—not internal routing.

Community	Action
`203314:220:1`	Prepend 1x outside Hats Network
`203314:220:2`	Prepend 2x outside Hats Network
`203314:220:3`	Prepend 3x outside Hats Network
`203314:220:4`	Prepend 4x outside Hats Network
`203314:220:5`	Prepend 5x outside Hats Network

Usage: Deprioritize specific prefixes for inbound traffic engineering.

Usage Examples

Example 1: Local Traffic Only

Announce a prefix only within a specific region:

# Announce to Asia West only
203314:2:1         # Disable cross-region

Example 2: Deprioritize Backup Prefix

Make a backup prefix less attractive:

# Deprioritize via path prepending
203314:220:3      # Prepend 3x AS203314

Example 3: Selective Peering

Announce only to specific peer types:

# Announce to peering and customers only
203314:1:0        # Do not send to upstream

Example 4: Exclude Location

Prevent announcement via specific location:

# Exclude PoP-specific announcement
203314:202:301    # Do not send via Seattle

Example 5: Combined Control

Combine multiple communities for complex policies:

# Deprioritized, Asia-only, no upstream
203314:1:0        # No upstream
203314:2:1         # Asia only
203314:220:2      # Prepend 2x

Implementation Notes

Best Practices:

Test before production: Use 203314:220:1 (1x prepend) to verify communities work
Monitor impact: Check route servers and looking glasses after applying changes
Document your policies: Keep track of which prefixes use which communities
Use conservative prepends: 3x prepend is usually sufficient; 5x is extreme

PoP Codes — Reference for PoP numbers (XXX) in geographic restrictions
Region Codes — Reference for region numbers (XX) in geographic restrictions
Internal Communities — Communities we attach to routes we announce

Important: Control communities are applied to routes you announce to AS203314. They do not affect routes we announce to you.

Control BGP Communities

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